update version from 0.4-SNAPSHOT to 0.5-SNAPSHOT
Better configuration for the JEObjectDatbase bulk load thread pool.

Use a thread factory that produces identifiable thread named and reduce
the number of worker threads taking into acount that there are two
databases running. Also use a ThreadPoolExecutor that runs on the caller thread
whent the pool is full to avoid large queues that might end up in OOM exceptions
guard RevTreeBuilder from an unchecked exception is the restulting tree is empty